Means for supporting the inner member of a double-walled tank



Feb. 13, 1962 D. R. CLAXTON 3,021,027

MEANS FOR SUPPORTING THE INNER MEMBER OF A DOUBLE-WALLED TANK Filed Oct. 8, 1958 2 Sheets-Sheet 1 INVENTOR DAVID R. CLAXTON ATTORNEY Feb. 13, 1962 D. R. CLAXTON MEANS FOR SUPPORTING THE INNER MEMBER OF A DOUBLE-WALLED TANK 2 Sheets-Sheet 2 Filed Oct. 8, 19.58

DAVID R. CLAXTON ATTORNEYS r 3,021,027 Unlted P atent Patented Feb.13,1962

3,021,027 MEANS FOR SURPORTING THE INNER MEMBER OF A DOUBLE-WALLED TANK David R. Claxton, 90 Maple St., Wenharn, Mass. Filed st 8. 1958. Ser. No. 766,038 1 Claim. ((31. 220-15) This invention relates to double-walled closed tanks for transporting liquids, and more particularly to improved connecting means between the outer and inner members by which the inner member is supported within the outer member but not in contact therewith.

Considerable quantities of liquids of various kinds are shipped in tank trucks, that is, elongated horizontal tanks which are mounted on motor trucks. Such tanks are customarily made of steel and in many instances are double walled, that is, an inner tank is encased in a similarly shaped but slightly larger outer tank and supported therein with clearance all around, so that the inner and outer tanks do not touch each other. When such tanks are subjected to ditferences of temperature, as when the inner tank is filled with a hot liquid while the outer tank is exposed to a cooler atmosphere, rela tive thermal longitudinal and radial expansion or contraction of the inner and outer tanks must be provided for. It is an object of the present invention to connect the inner and outer tanks to each other in such a manner as to support the inner tank clear of contact with the outer tank and to avoid harmful strains from thermal expansion. This is done by linkage hereinafter described and illustrated on the drawings, of which- FIGURE 1 is an elevational view of a double-walled tank embodying the invention, part of the outer wall being broken away;

FIGURE 2 is a sectional view on the line 22 of FIG- URE 1;

FIGURE 3 is a perspective view, on a larger scale, of one of the link members shown in FIGURE 1; and

FIGURE 4 is a perspective view, on a larger scale, of another link member shown in FIGURE 1.

The drawing illustrates a typical elongated cylindrical double walled tank. The tank comprises an inner tank surrounded by an outer tank 12 which is of substantially the same shape but slightly larger size. The outer tank may have any desired number of channel members 14 surrounding it circumferentially for strength. The inner tank 10 is held against longitudinal movement relative to the outer tank 12 by a number of straps or rods 16 which are welded to the outer surface of the inner tank 10 at one end thereof and also to the adjacent inner surface at the end of the outer tank 12. One such strap is illustrated in FIGURE 1 but any desired number may be employed.

According to the invention the inner tank is supported within the outer tank in spaced relation thereto by means which permit thermal expansion of either tank without setting up undesirable stresses in the tanks or in the connecting means. Such means consists of a suitable number of links which are pivotally attached to the peripheral surface of the inner tank and project substantially tangentially thereto, the other end of each link being secured to the inner surface of the outer tank 12. These links are distributed around the circumference of the inner tank and project therefrom in the same sense. As indicated in FIGURE 1 there may be two or more circular series of such links, each series being preferably but not necessarily in a common plane which is perpendicular to the axis of the tanks. One series, consisting of a number of links 20, is located near the end of the tank to which the straps 16 are secured. One end of each of the links is pivotally secured to a pair of ears 22 welded or otherwise secured to the skin of the inner tank 10. The other end of each link 20 is pivotally secured to a pair of ears 24 welded or otherwise secured to the inner surface of the outer tank 12. As illustrated in FIGURE 1, the pivot joints between the links 20 and the two tanks are such as will allow the links freedom of movement in the common plane in which the links lie, that is, a plane perpendicular to the axis of the tanks. However, if preferred, links having greater freedom of movement such as would be afforded by ordinary ball and socket joints at the ends of the links may be provided.

Near the other end of the tank and at spaced intervals between, if desired, other links may be provided. As shown, a circular series of links 30 connect the inner and outer tanks near the end remote from the straps 16. The links 30 are designed to provide universal joints between the joint fittings 32 on the inner tank and the joint fittings 34 which are mounted on the inner surface of the outer tank 12. As indicated in FIGURE 2, four such links are provided, these being symmetrically arranged around the circumference of the inner tank 10, but other numbers of links may be provided in each series. As illustrated in FIGURE 4 each of the links 30 has a pin receiving member 36 at one end to fit pivotally in the fitting 32 which is secured to the inner tank 10, and a member 38 at its other end which has a pivoted connection with the fitting 34. These pivot connections provide for automatic adjustment of the inner tank within the outer tank when either tank expands or contracts radially in response to a change of temperature. If, for example, an inner tank as seen in FIGURE 2, should contract materially by being chilled, it would simply rotate very slightly in a counterclockwise direction. Since relative thermal changes in the two tanks also result in differences of longitudinal expansion or contraction, the links '30 are made to provide a limited freedom of movement between the ends of the links in a direction lengthwise of the tank. For this purpose each link 30 has articulated joints 40 and 42 to permit relative rocking movement of the joints at the end of the link 30. Each link 30 thus provides the equivalent of a universal joint between the inner and outer tanks. The same effect can be obtained, if desired, by ordinary ball and socket joints at the ends of each link. Thus the links 20 and 30 provide for automatic adjustment when either of the tanks is thermally expanded or contracted relatively to the other, and the links 30 which are more or less remote from the end straps 16 also provide for relative longitudinal expansion or contraction of the two tanks. By means of these articulated joints at the ends of the links harmful stresses between the tanks are avoided but the tanks are maintained in their relative positions with a substantially constant clearance around their circumferences and at their ends.

I claim:

A double-walled tank comprising an inner cylindrical tank and a similarly shaped outer tank enclosing said inner tank, and means mechanically connecting said inner and outer tanks, said means comprising rigid connecting members at one end of the inner tank secured to the inner and outer tanks to prevent relative longitudinal movement thereof, a series of rigid links distributed around the circumference of the inner tank near said end thereof and extending substantially tangentially therefrom in the same sense to the outer tank, said links having pivoted joints at their ends connecting them to said tanks with freedom of movement in at least a plane perpendicular to the axis of the tanks, and a second series of links near the other end of the inner tank extending from the inner tank substantially tangentially to the outer tank in the same said sense and spaced around the circumference of said inner tank, the links of said References Cited in the file of this patent UNITED STATES PATENTS Heylandt July 5, 1932 4 Picard Sept. 20, 1932 Hansen et a1. Apr. 19, 1949 Schilling July 4, 1950 Johnston Dec. 9, 1958 Hampton Feb. 23, 1960 Yeager Mar. 1, 1960 

